1. Field of the Invention
The present invention relates to microwave ovens, and more particularly, to a microwave oven comprising a control panel having an air discharging structure.
2. Description of the Related Art
Generally, a microwave oven is an appliance which cooks food using microwaves. That is, the microwave oven cooks food by heating the interior of the food through a dielectric heating method. The microwave oven includes a cooking cavity which receives food, and a magnetron which irradiates microwaves into the cooking cavity. A door is mounted to a front of the cooking cavity to open or close the cooking cavity. A control panel is mounted to a front of a machine room having electrical devices including the magnetron. The control panel is provided with a plurality of control pads to control an operation of the microwave oven, and a display to display an operating state of the microwave oven.
FIG. 1 shows a control panel of a conventional microwave oven. The control panel includes a panel casing 1. A membrane board 2 having a thin panel shape is mounted to a front surface of the panel casing 1. A cover sheet 3 is attached to a front surface of the membrane board 2. Several input keys are printed on an outer surface of the cover sheet 3. A circuit board 4 is mounted to a rear surface of the panel casing 1. An opening 6 is provided at an upper portion of the panel casing 1 so as to receive a display 5. The display 5 comprises an LCD or a touch screen.
The front of the panel casing 1 is recessed by a predetermined depth to form a flat membrane board seat 8, so as to seat the membrane board 2 in the membrane board seat 8. The membrane board 2 is attached to the membrane board seat 8 using a double-sided adhesive tape (not shown) or an adhesive (not shown). The cover sheet 3 is attached to the front surface of the membrane board 2, in the same manner as the membrane board 2 is attached to the front surface of the panel casing 1.
However, the conventional control panel has a problem in that air may flow between the panel casing 1 and the membrane board 2, or between the membrane board 2 and the cover sheet 3 where the membrane board 2 is attached to the front surface of the panel casing 1, or the cover sheet 3 is attached to the front surface of the membrane board 2 using an adhesive tape or an adhesive. Accordingly, the membrane board 2 may come off from the panel casing 1, or the cover sheet 3 may come off from the membrane board 2 due to air bubbles, which are difficult to remove, resulting from the air flow.
Furthermore, air existing between the membrane board 2, the cover sheet 3, and the panel casing 1, which are attached to each other, may expand due to a temperature variation around the microwave oven as the microwave oven is used. Therefore, the cover sheet 3 may swell, thus deteriorating the appearance of the control panel.